How can I learn how to manage my time better?

Unfortunately uni can be like that however, you could have a timetable but that doesn't mean you will follow it. It's a case of being responsible and prioritising what is important. Your friends are not going anywhere, you can record the shows, take one day out to cook for the five days and freeze the food etc or each of your friend cooks for everyone one day of the week, there are a lot of ways that you can do things quickly and still have time to enjoy your life. You sound disorganised if anything. You shouldn't let your work suffer though.